1. Field of the Invention
The present invention is generally related to an antibiofouling coating composition, and more particularly to an antibiofouling coating composition, antibiofouling membrane and method for forming the same.
2. Description of the Prior Art
In biological applications, particularly biomedical technology, antibiofouling control is a very important topic. Especially, it is highly not anticipated to have nonspecific adsorption between biomolecules and the surface of materials in use. For example, adsorption or adherence of a small amount of biomolecules such as proteins usually causes propagation of unwanted bio-fouling reaction to result in inability of accomplishing the originally expected function.
The so-called “antibiofouling surface” means the surface of a material or an object is free of adsorption or adherence of biomolecules such as proteins, bacteria. The physical and chemical properties to constitute an “antibiofouling surface” are unclear yet although there are reports which postulate that an antibiofouling surface should be electrically neutral, hydrophilic, and have hydrogen bond acceptors but not hydrogen bond donors. However, there are many exceptions even fulfilling the above characteristics, that is, still being biofouling surfaces. (referring to Ostuni, E. et al., Langmuir (2001) 17(18)5605 and Luk, Y-Y., et al., Langmuir (2000) 16(24)9604)
Furthermore, regarding the rules of reducing biofouling, for example, it is believed that the increase of hydrophilic moieties on a hydrophobic material surface can effectively reduce its biofouling ability due to the reduced hydrophobic interactions. For example, the inventors reported that an ordered layer structure of hydrophilic domain and hydrophobic domain can improve bio-fouling resistance of the hydrophobic surface (Chang, Y. et at, J. Biomed. Mater. Res. 2010, 93, 400-408).
However, in order to process a surface to become an antibiofouling surface, a coating agent or coating composition should not only have antibiofouling surface ability after becoming a coating but also be anchored or adhered to the surface which is to be processed.
Although the above reports or other previous reports disclose various general rules or methods to control the antibiofouling characteristic, materials fulfilling these rules as a coating agent or coating composition may not have effective antibiofouling ability.
Besides, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or polypropylene (PP) membranes are widely used as an ultrafiltration membrane because of their outstanding properties such as chemical resistance and thermal stability. However, the bio-fouling problem of these membranes was frequently criticized. In order to improve antibiofouling ability, strategies like blending PEG containing polymers before membrane formation or surface grafting of PEG moiety is proposed. In the polymer blending method before membrane formation, only limited PEG moieties can be incorporated into the membrane and the stability is not promising so that the improvement of the antibiofouling ability is limited. Although surface grafting has been shown highly efficient in improving bio-fouling resistance, large scale surface modification through this technique is still difficult and surface grafting also has problems of permanently changing the chemical and other properties of the membrane, low homogeneity, and high production cost. Therefore, an effective antibiofouling coating agent or coating composition is important and required to have such a hydrophobic membrane be surface treated and become being antibiofouling.